1. Tandem supercross. pretty much self explanatory, 4 tandems duking it out against each other. because multiplayer goes up to 8 right? why not four tandems? I can already imagine the carnage, and yelling

2.A four player tandem? pretty sure you thought about it. but eh, looks fun to me.

3 Seperate leaderboards for tandem runs. A few other games what i play have some seperate leaderboards because they have a different ruleset applied to them. and thus not breaking the normal leaderboards.